This is a neat trick, to hide file names of files and folders in thumbnail view in windows Xp.
Just go to any other view other than the thumbnail view (using the views dropdown).
Now press and hold the shift button and then change the view to thumbnail view.
You will find that the file names are not visible now.
However if you switch to other views the file names would be visible.
To make the file names visible again, repeat the same holding the shift button, changing the view from any other view to the thumbnails view to get the file names back.